where \(F_{1}(0)=F_{2}(0)\) . Now, the form factors appearing in Eqs. (REF ) to () can be related to each other by means
of Ward identities [1]}, [2]}, i.e.,
\(\left\langle V(k,\varepsilon )\left|\bar{s}\sigma _{\mu \nu }q^{\nu }b\right|B(p)\right\rangle =-(m_{b}+m_{s})\left\langle V(k,\varepsilon )\left|\bar{s}\gamma _{\mu }b\right|B(p)\right\rangle  \\\left\langle V(k,\varepsilon )\left|\bar{s}\sigma _{\mu \nu }q^{\nu }\gamma ^{5}b\right|B(p)\right\rangle = (m_{b}-m_{s})\left\langle V(k,\varepsilon )\left|\bar{s}\gamma _{\mu }\gamma _{5}b\right|B(p)\right\rangle  \ .\) 
